Bismuth vanadate-based microwave dielectric ceramic material and preparation method and application thereof

Abstract

The invention discloses a bismuth vanadate-based microwave dielectric ceramic material and a preparation method and application thereof. The ceramic material is (1‑a‑b‑c‑d‑e‑f)BiVO4‑a(Li 0.5 Bi 0.5 )MoO4‑b(Na 0.5 Bi 0.5 )MoO4‑c(K 0.5 Bi 0.5 )MoO4‑d(Li 0.5 La 0.5 )WO4‑e(Li 0.5 Nd 0.5 )WO4‑fBi(Fe 1 / 3 W 2 / 3 )O4. The preparation method includes batching, pre-firing and sintering. The ceramic material of the present invention can be sintered at low temperature without adding any sintering aid, has excellent dielectric constant, quality factor and resonant frequency temperature coefficient, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic ceramics, and relates to a bismuth vanadate-based microwave dielectric ceramic material, a preparation method and an application thereof, and in particular to a bismuth vanadate-based microwave dielectric ceramic material sintered at a low temperature, a preparation method and an application thereof. Background Art

[0002] Microwave dielectric ceramics can perform important functions such as dielectric isolation, dielectric waveguide and dielectric resonance in microwave frequency band circuits, and have broad application prospects in many fields such as satellite communications, Beidou navigation and electronic countermeasures. With the rapid development of mobile communication technology, 5G / 6G is reshaping the pattern of digital society. Its ultra-high frequency, large bandwidth and low latency characteristics will have a profound impact on human life and industrial upgrading. In the process of supporting 5G / 6G communication technology to achieve ultra-high-speed data transmission, microwave dielectric ceramic materials play a key basic supporting role. As a type of functional material, microwave dielectric ceramics have been widely used in antennas, filters and other components of microwave communication systems due to their serialized dielectric constants, low dielectric losses and good temperature stability.

[0003] As electronic information technology continues to develop towards high frequency and digitalization, research focuses are increasingly concentrated on the miniaturization, integration and multifunctionality of components. Low temperature co-fired ceramic (LTCC) technology is a multi-layer substrate process technology widely used in electronic packaging, radio frequency communications, sensors and other fields. It requires the sintering temperature of ceramic materials to be lower than 950°C and to be co-fired with conductor electrodes such as Au and Ag. LTCC materials have excellent high frequency, low loss and high-speed transmission characteristics, are suitable for the application of microwave and millimeter wave circuits, and have good compatibility with thin film multi-layer wiring technology, which can achieve higher assembly density and better performance of hybrid multi-layer substrates and hybrid multi-chip modules.

[0004] However, it is difficult for existing low-temperature sintered ceramic material systems to simultaneously meet the target dielectric constant, high Q×f value and near-zero τ f The requirement of the value limits its application in microwave communication. At present, the sintering temperature of microwave dielectric ceramics is mostly concentrated in the range of 900℃ to 1300℃. Most of them need to reduce the sintering temperature by adding sintering aids, but sintering aids may introduce second phases or impurity ions, which will lead to the deterioration of dielectric properties and make it difficult to use in LTCC. If the sintering temperature is reduced to below 900℃, the quality factor or resonant frequency temperature coefficient of the ceramic will often be sacrificed. Therefore, how to develop multiple high-performance compatible low-temperature sintered microwave dielectric ceramics has become a top priority. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a bismuth vanadate-based microwave dielectric ceramic material that can be sintered at low temperature without adding any sintering aids, has a high dielectric constant, a high quality factor and a resonant frequency temperature coefficient with a wide adjustable range, as well as a preparation method and application thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] A bismuth vanadate-based microwave dielectric ceramic material, wherein the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is as shown in formula (1):

[0008] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0009] In formula (1), 0

[0010] The above-mentioned bismuth vanadate-based microwave dielectric ceramic material, preferably, the dielectric constant ε of the bismuth vanadate-based microwave dielectric ceramic material is r The value of the quality factor Q×f is 5100GHz~8000GHz, and the temperature coefficient of resonant frequency TCF is between -40ppm / ℃~55ppm / ℃.

[0011] As a general technical concept, the present invention also provides a method for preparing the above-mentioned bismuth vanadate-based microwave dielectric ceramic material, comprising the following steps:

[0012] (1) chemical raw materials Bi2O3, Li2CO3, Na2CO3, K2CO3, La2O3, Nd2O3, V2O5, MoO3, WO3 and Fe2O3 are prepared according to the chemical expression of formula (1), and mixed to obtain a mixed material;

[0013] ​(2) ball-milling the mixture, drying it, and sieving it, and pre-calcining the sieved mixed powder at 600° C. to 650° C. to obtain a pre-calcined powder;

[0014] (3) The pre-sintered powder is crushed, ball-milled for a second time, dried, granulated and double-sieved to obtain porcelain powder;

[0015] (4) The ceramic powder is pressed into a shape and sintered at a low temperature of 780°C to 840°C in air to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0016] In the above-mentioned method for preparing bismuth vanadate-based microwave dielectric ceramic material, preferably, in step (4), the low-temperature sintering time is 2h to 4h.

[0017] In the above-mentioned method for preparing bismuth vanadate-based microwave dielectric ceramic material, preferably, in step (2), the ball milling medium for the first ball milling is anhydrous ethanol, the time for the first ball milling is 8h to 10h, the drying temperature is 80°C to 100°C, the mesh size of the sieving is 60 mesh to 80 mesh, and the pre-burning time is 4h to 5h.

[0018] In the above-mentioned method for preparing bismuth vanadate-based microwave dielectric ceramic materials, preferably, in step (3), the ball milling medium for the secondary ball milling is anhydrous ethanol, the time for the secondary ball milling is 6h to 8h, the drying temperature is 80°C to 100°C, and the double-layer screening is first through a 40-mesh to 60-mesh sieve and then through a 80-mesh to 100-mesh sieve.

[0019] As a general technical concept, the present invention also provides an application of the above-mentioned bismuth vanadate-based microwave dielectric ceramic material or the bismuth vanadate-based microwave dielectric ceramic material prepared by the above-mentioned preparation method in the field of low-temperature co-fired ceramic technology.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] (1) The main feature of the bismuth vanadate-based microwave dielectric ceramic material of the present invention is that it uses low-melting-point oxides Bi2O3 and V2O5 as the main elements, combined with Li2CO3, Na2CO3, K2CO3, La2O3, Nd2O3, MoO3, WO3 and Fe2O3 raw materials, and under a specifically designed chemical expression, it is possible to sinter this dielectric ceramic at a low temperature. Without adding any sintering aids, the present invention can sinter a new type of functional ceramic with compactness and excellent microwave dielectric properties within a relatively very low temperature range (780°C-840°C). This type of ceramic can be used as a dielectric material such as a radio frequency multilayer ceramic capacitor, a chip-type microwave dielectric resonator or filter, a low-temperature co-fired ceramic system (LTCC), a ceramic substrate, and a multi-chip module (MCM).

[0022] The bismuth vanadate-based microwave dielectric ceramic material of the present invention has the advantages of high dielectric constant, high quality factor and resonant frequency temperature coefficient with a wide adjustable range. r The value of the quality factor Q×f is 53~81, the value of the quality factor Q×f is 5100GHz~8000GHz, and the temperature coefficient of resonance frequency TCF is between -40ppm / ℃~55ppm / ℃, which makes it suitable for the needs of low temperature co-fired ceramic (LTCC) technology and expands its application range.

[0023] (2) The method of the present invention adopts solid phase reaction sintering to prepare bismuth vanadate-based microwave dielectric ceramic materials. First, a suitable formula, suitable initial oxides and carbonates are designed, the raw materials are evenly mixed by a first ball milling, the raw materials are initially reacted by a pre-sintering process, and the particle size of the reactants is refined by a second ball milling. Finally, the desired ceramic sample is sintered in a relatively low temperature range of 780°C-840°C. The preparation process of the present invention is simple and easy, the sample phase is single, and the comprehensive dielectric properties are excellent.

[0024] (3) The bismuth vanadate-based microwave dielectric ceramic material of the present invention can be applied in the field of low-temperature co-fired ceramic technology and has good application prospects. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0026] Example 1

[0027] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0028] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0029] Where a=0.1, b=0, c=0, d=0.05, e=0.01, f=0.01,

[0030] Specifically, 0.83BiVO4-0.1(Li 0.5 Bi 0.5 )MoO4-0.05(Li 0.5 La 0.5 )WO4-0.01(Li 0.5 Nd 0.5 )WO4-0.01Bi (Fe 1 / 3 W 2 / 3 )O4.

[0031] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0032] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, V2O5, MoO3, WO3, La2O3, Nd2O3 and Fe2O3 were mixed at 0.83BiVO4-0.1(Li 0.5 Bi 0.5 )MoO4-0.05(Li 0.5 La 0.5 )WO4-0.01(Li 0.5 Nd 0.5 )WO4-0.01Bi(Fe 1 / 3W 2 / 3 )O4 ingredients to obtain a mixture.

[0033] (2) The mixture was fully mixed in anhydrous ethanol and ball-milled (one time) for 8 hours, then dried at 80°C, passed through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0034] (3) The pre-sintered powder is crushed and ball-milled (secondary ball-milling) in anhydrous ethanol for 6 hours. After being ground into fine powder, it is dried at 80°C and then granulated. It is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0035] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 810° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0036] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0037] Sintered into porcelain in air at 810℃, dielectric constant ε at microwave frequency r = 53.1, quality factor Q×f = 7240GHz, temperature coefficient of resonant frequency TCF = 30.7 ppm / ℃ (25℃-85℃).

[0038] Example 2

[0039] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0040] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0041] Where a=0.04, b=0.04, c=0, d=0.04, e=0.04, f=0.01,

[0042] Specifically, 0.83BiVO4-0.04(Li 0.5 Bi 0.5 )MoO4-0.04(Na 0.5 Bi 0.5 )MoO4-0.04(Li 0.5 La 0.5 )WO4-0.04 (Li 0.5 Nd 0.5 )WO4-0.01Bi(Fe 1 / 3 W 2 / 3 )O4.

[0043] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0044] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, Na2CO3, V2O5, MoO3, WO3, La2O3, Nd2O3 and Fe2O3 were prepared according to the conditions of 0.83BiVO4-0.04(Li 0.5 Bi 0.5 )MoO4-0.04(Na 0.5 Bi 0.5 )MoO4-0.04(Li 0.5 La 0.5 )WO4-0.04(Li 0.5 Nd 0.5 )WO4-0.01Bi(Fe 1 / 3 W 2 / 3)O4 ingredients to obtain a mixture.

[0045] (2) The mixture was fully mixed in anhydrous ethanol and ball-milled for 8 hours, then dried at 80°C, passed through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0046] (3) The pre-calcined powder is crushed and ball-milled in anhydrous ethanol for 6 hours. After being ground into fine powder, it is dried at 80°C and then granulated. It is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0047] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 820° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0048] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0049] Sintered into porcelain in air at 820℃, dielectric constant ε at microwave frequency r = 56.8, quality factor Q×f = 7852GHz, temperature coefficient of resonant frequency TCF = 14.6 ppm / ℃ (25℃-85℃).

[0050] Example 3

[0051] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0052] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0053] In the formula, a=0.08, b=0, c=0.01, d=0.04, e=0.02, f=0.01,

[0054] Specifically, 0.84BiVO4-0.08(Li 0.5 Bi 0.5 )MoO4-0.01(K 0.5 Bi0.5 )MoO4-0.04(Li 0.5 La 0.5 )WO4-0.02 (Li 0.5 Nd 0.5 )WO4-0.01Bi(Fe 1 / 3 W 2 / 3 )O4.

[0055] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0056] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, K2CO3, V2O5, MoO3, WO3, La2O3, Nd2O3 and Fe2O3 were mixed at 0.84BiVO4-0.08(Li 0.5 Bi 0.5 )MoO4-0.01(K 0.5 Bi 0.5 )MoO4-0.04(Li 0.5 La 0.5 )WO4-0.02(Li 0.5 Nd 0.5 )WO4-0.01Bi(Fe 1 / 3 W 2 / 3 )O4 ingredients to obtain a mixture.

[0057] (2) The mixture is added with anhydrous ethanol and fully mixed and ball-milled for 8 hours, then dried at 80°C, sieved through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0058] (3) The pre-calcined powder is crushed, ball-milled with anhydrous ethanol for 6 hours, dried at 80°C after being ground into powder, and then granulated. The powder is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0059] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 820° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0060] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0061] Sintered into porcelain in air at 820℃, dielectric constant ε at microwave frequency r =53.2, quality factor Q×f = 7658GHz, resonant frequency temperature coefficient TCF = 5.5 ppm / ℃ (25℃-85℃).

[0062] Example 4

[0063] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0064] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0065] Where a=0.08, b=0, c=0, d=0.01, e=0.01, f=0.03,

[0066] Specifically, 0.87BiVO4-0.08(Li 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4-0.01(Li 0.5 Nd 0.5 )WO4-0.03 Bi(Fe 1 / 3 W 2 / 3 )O4.

[0067] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0068] (1) Chemical raw materials Bi2O3, Li2CO3, V2O5, MoO3, WO3, La2O3, Nd2O3 and Fe2O3 were mixed at 0.87BiVO4-0.08(Li 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4-0.01(Li 0.5 Nd 0.5 )WO4-0.03Bi(Fe 1 / 3 W 2 / 3 )O4 ingredients to obtain a mixture, wherein the chemical raw materials are of analytical grade.

[0069] (2) The mixture is added with anhydrous ethanol and fully mixed and ball-milled for 8 hours, then dried at 80°C, sieved through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0070] (3) The pre-calcined powder is crushed, ball-milled with anhydrous ethanol for 6 hours, dried at 80°C after being ground into powder, and then granulated. The powder is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0071] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 800° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0072] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0073] Sintered into porcelain at 800℃ in air, the dielectric constant ε at microwave frequency r = 78.7, quality factor Q×f value = 5142GHz, resonant frequency temperature coefficient TCF = 33.8 ppm / ℃ (25℃-85℃).

[0074] Example 5

[0075] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0076] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0077] In the formula, a=0.01, b=0, c=0.05, d=0.01, e=0.02, f=0.02,

[0078] Specifically, 0.89BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.05(K 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4-0.02 (Li 0.5 Nd 0.5)WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4.

[0079] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0080] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, K2CO3, La2O3, Nd2O3, V2O5, MoO3, Fe2O3 and WO3 were mixed according to the formula 0.89BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.05(K 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4- 0.02(Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4 ingredients to obtain a mixture.

[0081] (2) The mixture is added with anhydrous ethanol and fully mixed and ball-milled for 8 hours, then dried at 80°C, sieved through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0082] (3) The pre-calcined powder is crushed, ball-milled with anhydrous ethanol for 6 hours, dried at 80°C after being ground into powder, and then granulated. The powder is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0083] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 800° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0084] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0085] Sintered into porcelain at 800℃ in air, the dielectric constant ε at microwave frequency r = 74.6, quality factor Q×f value = 5731GHz, resonant frequency temperature coefficient TCF = 53.9 ppm / ℃ (25℃-85℃).

[0086] Example 6

[0087] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0088] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0089] Where a=0.01, b=0.04, c=0, d=0.01, e=0.01, f=0.02,

[0090] Specifically, 0.91BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.04(Na 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4-0.01 (Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4.

[0091] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0092] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, Na2O3, La2O3, Nd2O3, V2O5, MoO3, Fe2O3 and WO3 were mixed according to the formula 0.91BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.04(Na 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4- 0.01(Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4 ingredients to obtain a mixture.

[0093] (2) The mixture is added with anhydrous ethanol and fully mixed and ball-milled for 8 hours, then dried at 80°C, sieved through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0094] (3) The pre-calcined powder is crushed, ball-milled with anhydrous ethanol for 6 hours, dried at 80°C after being ground into powder, and then granulated. The powder is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0095] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 810° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0096] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0097] Sintered into porcelain in air at 810℃, dielectric constant ε at microwave frequency r = 80.5, quality factor Q×f value = 6506GHz, resonant frequency temperature coefficient TCF = 41.0 ppm / ℃ (25℃-85℃).

[0098] Example 7

[0099] A bismuth vanadate-based microwave dielectric ceramic material of the present invention, the chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1):

[0100] (1-abcdef)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1)

[0101] Where a=0.01, b=0.03, c=0.02, d=0.01, e=0.01, f=0.02,

[0102] Specifically, 0.90BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.03(Na 0.5 Bi 0.5 )MoO4-0.02(K 0.5 Bi0.5 )MoO4-0.01 (Li 0.5 La 0.5 )WO4- 0.01(Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4.

[0103] A method for preparing a bismuth vanadate-based microwave dielectric ceramic material of this embodiment comprises the following steps:

[0104] (1) Analytically pure chemical raw materials Bi2O3, Li2CO3, Na2O3, K2CO3, La2O3, Nd2O3, V2O5, MoO3, Fe2O3 and WO3 were mixed according to the formula 0.90BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.03(Na 0.5 Bi 0.5 )MoO4-0.02(K 0.5 Bi 0.5 ) MoO4-0.01 (Li 0.5 La 0.5 )WO4-0.01(Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4 ingredients to obtain a mixture.

[0105] (2) The mixture is added with anhydrous ethanol and fully mixed and ball-milled for 8 hours, then dried at 80°C, sieved through a 60-mesh sieve, and pre-calcined at 600°C for 4 hours to obtain a pre-calcined powder.

[0106] (3) The pre-calcined powder is crushed, ball-milled with anhydrous ethanol for 6 hours, dried at 80°C after being ground into powder, and then granulated. The powder is then sieved through a double layer of 40-mesh and 80-mesh sieves to obtain porcelain powder.

[0107] (4) The ceramic powder is pressed into a columnar shape as required, and then sintered in air at 815° C. for 2 hours to obtain a bismuth vanadate-based microwave dielectric ceramic material.

[0108] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this embodiment reaches the following indicators:

[0109] Sintered into porcelain at 815℃ in air, dielectric constant ε under microwave r = 77.6, quality factor Q×f value = 6032GHz, temperature coefficient of resonant frequency under microwave TCF = -36.2 ppm / ℃ (25℃-85℃).

[0110] Comparative Example 1

[0111] A bismuth vanadate-based microwave dielectric ceramic material and a preparation method thereof are basically the same as those in Example 7, except that: f is 0.09, that is, the chemical expression is 0.83BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.03(Na 0.5 Bi 0.5 )MoO4-0.02(K 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4- 0.01(Li 0.5 Nd 0.5 )WO4-0.09Bi(Fe 1 / 3 W 2 / 3 )O4.

[0112] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this comparative example reaches the following indicators:

[0113] Sintered into porcelain in air at 815℃, dielectric constant ε at microwave frequency r = 63.2, quality factor Q×f value = 4826 GHz, temperature coefficient of resonant frequency TCF = 91.0 ppm / ℃ (25℃-85℃).

[0114] Comparative Example 2

[0115] A bismuth vanadate-based microwave dielectric ceramic material and a preparation method thereof are basically the same as those in Example 7, except that: e is 0.07, that is, the chemical expression is 0.84BiVO4-0.01(Li 0.5 Bi 0.5 )MoO4-0.03(Na 0.5 Bi 0.5 )MoO4-0.02(K 0.5 Bi 0.5 )MoO4-0.01(Li 0.5 La 0.5 )WO4- 0.07(Li 0.5 Nd 0.5 )WO4-0.02Bi(Fe 1 / 3 W 2 / 3 )O4.

[0116] After testing, the performance of the bismuth vanadate-based microwave dielectric ceramic material prepared in this comparative example reaches the following indicators:

[0117] Sintered into porcelain in air at 815℃, dielectric constant ε at microwave frequency r = 57.2, quality factor Q×f value = 5012GHz, resonant frequency temperature coefficient TCF = 68.0 ppm / ℃ (25℃-85℃).

[0118] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A bismuth vanadate-based microwave dielectric ceramic material, characterized in that: The chemical expression of the bismuth vanadate-based microwave dielectric ceramic material is shown in formula (1): (1-a-b-c-d-e-f)BiVO4-a(Li 0.5 Bi 0.5 )MoO4-b(Na 0.5 Bi 0.5 )MoO4-c(K 0.5 Bi 0.5 )MoO4-d(Li 0.5 La 0.5 )WO4-e(Li 0.5 Nd 0.5 )WO4-fBi(Fe 1 / 3 W 2 / 3 )O4, formula (1) In formula (1), 0 < a ≤ 0.1, 0 ≤ b ≤ 0.05, 0 ≤ c ≤ 0.05, 0 < d ≤ 0.05, 0 < e ≤ 0.05, 0 < f ≤ 0.

07.

2. The bismuth vanadate-based microwave dielectric ceramic material according to claim 1, characterized in that: The dielectric constant ε of the bismuth vanadate-based microwave dielectric ceramic material r The value of the quality factor Q×f is 5100GHz~8000GHz, and the temperature coefficient of resonant frequency TCF is between -40ppm / ℃~55ppm / ℃.

3. A method for preparing the bismuth vanadate-based microwave dielectric ceramic material according to claim 1 or 2, characterized in that: The following steps are involved: (1) chemical raw materials Bi2O3, Li2CO3, Na2CO3, K2CO3, La2O3, Nd2O3, V2O5, MoO3, WO3 and Fe2O3 are prepared according to the chemical expression of formula (1), and mixed to obtain a mixed material; (2) ball milling the mixture, drying it and then sieving it, and pre-calcining the sieved mixed powder at 600° C. to 650° C. to obtain a pre-calcined powder; (3) The pre-fired powder is crushed, ball-milled for a second time, dried, granulated and double-sieved to obtain porcelain powder; (4) The ceramic powder is pressed into a shape and sintered at a low temperature of 780°C to 840°C in air to obtain a bismuth vanadate-based microwave dielectric ceramic material.

4. The method for preparing the bismuth vanadate-based microwave dielectric ceramic material according to claim 3, characterized in that: In step (4), the low-temperature sintering time is 2 h to 4 h.

5. The method for preparing the bismuth vanadate-based microwave dielectric ceramic material according to claim 3 or 4, characterized in that: In step (2), the ball milling medium of the first ball milling is anhydrous ethanol, the time of the first ball milling is 8h to 10h, the drying temperature is 80°C to 100°C, the mesh size of the sieving is 60 mesh to 80 mesh, and the pre-burning time is 4h to 5h.

6. The method for preparing the bismuth vanadate-based microwave dielectric ceramic material according to claim 3 or 4, characterized in that: In step (3), the ball milling medium of the secondary ball milling is anhydrous ethanol, the time of the secondary ball milling is 6h to 8h, the temperature of the drying is 80°C to 100°C, and the double-layer screening is first through a 40-mesh to 60-mesh sieve and then through a 80-mesh to 100-mesh sieve.

7. Use of the bismuth vanadate-based microwave dielectric ceramic material as claimed in claim 1 or 2 or the bismuth vanadate-based microwave dielectric ceramic material prepared by the preparation method as claimed in any one of claims 3 to 6 in the field of low-temperature co-fired ceramic technology.